Comparison of epifaunal assemblages between Cymodocea

nodosa and Caulerpa prolifera meadows in Gran Canaria

(eastern Atlantic)

Lydia Png González

Máster en Oceanografía

Universidad de Las Palmas de Gran Canaria

Director: Dr. Fernando Tuya Cortés

Tutor: Dr. Santiago Hernández León

Julio 2013

Comparison of epifaunal assemblages between and

Caulerpa prolifera meadows in Gran Canaria (eastern Atlantic)

Lydia Png-Gonzalez1*, Maite Vázquez-Luis2, Fernando Tuya1

1Centro en Biodiversidad y Gestión Ambiental, Marine Sciences Faculty, Campus

Tafira, Universidad de Las Palmas de Gran Canaria, 35017 Tafira, Las Palmas, Spain

2Instituto Español de Oceanografía, Centro Oceanográfico de Baleares. Muelle de

Poniente s/n, 07015 Palma de Mallorca, Spain

1 ABSTRACT

Epifaunal invertebrates are sensitive to changes in the identity of the dominant host plant, so assessing differences in the diversity, abundance and structure of epifaunal assemblages is particularly pertinent in areas where seagrasses have been replaced by alternative vegetation (e.g. green seaweeds). In this study, we aimed to compare the diversity, abundance and structure of epifaunal assemblages, with particular emphasis on amphipods, between meadows dominated by Cymodocea nodosa and the green algae Caulerpa prolifera on shallow soft bottoms of Gran Canaria Island, determining whether patterns were temporally consistent. The epifaunal assemblage structure (abundance and composition) consistently differed between both plants, being more diverse and abundant epifaunal assemblages associated with C. prolifera- dominated beds than those inhabiting C. nodosa meadows. Amphipods constituted ca.

70% of crustaceans for the overall study, including 37 belonging to 16 families.

The amphipods abundance recorded was ca. 3 times larger in C. prolifera-dominated beds (1248.13 ± 136.83 ind. m-2, mean ± SE) than in C. nodosa meadows (396.88 ±

77.36 ind. m-2). Multivariate analysis of the community showed significant differences between habitats, with a clear segregation of the species. For instance, Microdeutopus stationis, Dexamine spinosa, Aora spinicornis, Ischyrocerus inexpectatus and Apherusa bispinosa were more abundant in C. prolifera-dominated beds; while the new genus, new species of caprellid, Mantacaprella macaronensis, dominated in C. nodosa meadows. However, some species such as Pseudoprotella phasma and Ampithoe ramondi were found without significant differences in both habitats.

Keywords: Amphipoda, epifauna, assemblage structure, ecosystem services, seagrass,

Canary Islands.

2 1. Introduction

On subtidal soft bottoms, seagrasses form one of the most productive ecosystems worldwide, providing high-value ecosystem services such as delivery of food and habitat for a wide range of organisms (Costanza et al., 1997; Duffy, 2006;

Thomsen et al., 2012), support of commercial fisheries, nutrient cycling, sediment stabilization and sequestration of carbon (Duarte et al., 2000; Waycott et al., 2009).

Seagrasses, and the services they provide, are, however, threatened by impacts derived from coastal development and growing human population, as well as by impacts caused by climate change (Duarte, 2002; Orth et al., 2006; Waycott et al., 2009). Conservation of these valuable habitats is, therefore, important, particularly since seagrass meadows are declining worldwide, mainly in areas of intense human activities (Hughes et al.,

2009).

Cymodocea nodosa (Ucria) Ascherson is a seagrass distributed across the

Mediterranean Sea and adjacent areas of the Atlantic Ocean, including the

Macaronesian archipelagos of Madeira and the Canaries (Reyes et al., 1995; Tuya et al.,

2012). Meadows constituted by C. nodosa are the dominant vegetated communities on shallow soft substrates throughout the Canary Islands (Pavón-Salas et al., 2000; Barberá et al., 2005; Monterroso et al., 2012), where they provide food and shelter for diverse invertebrate and fish assemblages, including a ‘nursery’ habitat for larval and juvenile fish stages (Tuya et al., 2006; Espino et al., 2011a, 2011b). However, C. nodosa meadows are severely decreasing at local scales, as a result of a range of human- mediated impacts (Martínez-Samper, 2011; Tuya et al., 2013). In these coastal areas, the decline of C. nodosa seagrass meadows often results in the replacement by

3 opportunistic green algae of the genus Caulerpa, Caulerpa prolifera (Forsskål) J.V.

Lamouroux in particular (Martínez-Samper, 2011; Tuya et al., 2013).

Caulerpa prolifera is a native seaweed in the Canary Islands (Haroun et al.,

2003), forming extensive beds on soft bottoms in waters from ca. 5 to 50 m depth.

Several Caulerpa species contain caulerpenyne, a major secondary metabolite, which varies depending on the species, locations and seasons (Jung et al., 2002; Box et al.,

2010), and appears to possess toxic and feeding deterrent properties against faunal herbivores (Smyrniotopoulos et al., 2003). Caulerpenyne may also act as an antimitotic substance, preventing settlement of most epiphytes (Sánchez-Moyano et al., 2001a). In addition, the high sediment-retention capacity of Caulerpa beds induces organic enrichment (Hendriks et al., 2010), potentially altering the distribution and abundance of associated populations (Sánchez-Moyano et al., 2001a).

When seagrasses are replaced by seaweeds, the quantity and quality of habitat for associated faunal assemblages may be altered, as well as flows of energy and matter through the ecosystem (Thomsen et al., 2012). In particular, epifaunal invertebrates are sensitive to changes in plant abundance and structure (e.g. through plant attributes such as plant size, biomass, shoot density, etc.), so differences in the diversity, abundance and structure of invertebrate assemblages are expected between different types

(identities) of vegetation within the same geographical and environmental context

(Sirota and Hovel, 2006).

The aim of this study was to compare the diversity, abundance and structure of epifaunal assemblages between meadows dominated by Cymodocea nodosa and

Caulerpa prolifera on shallow soft bottoms of Gran Canaria Island, determining whether patterns were temporally consistent. Particular emphasis was concentrated on amphipod assemblages, since amphipods are one of the most quantitatively and

4 important groups of invertebrates associated with coastal vegetated habitats, while these organisms also play an important role as trophic resources for fish populations

(Sánchez-Jerez et al., 1999; Vázquez-Luis et al., 2009). In this sense, amphipods respond to habitat alterations and can, therefore, be used as an indicator of environmental impacts on vegetated habitats (Virnstein, 1987; Conradi et al., 1997;

Sánchez-Jerez et al., 2000; Vázquez-Luis et al., 2008, 2009).

2. Material and methods

2.1. Study area and sampling design

The study was carried out in Gran Canaria (Canary Islands, eastern Atlantic), at a range of localities across the island (Table 1) dominated by either subtidal mono- specific Cymodocea nodosa meadows or beds constituted by Caulerpa prolifera.

Table 1. Sampled localities to compare epifaunal assemblages between Cymodocea nodosa seagrass meadows and Caulerpa prolifera-dominated beds at Gran Canaria Island.

Habitat Locality UTM X UTM Y Depth (m) Date C. nodosa L1 421440 3080993 11.3 Nov’11 C. nodosa L2 462235 3082272 10 Nov’11 C. nodosa L1 461982 3081367 11.3 Oct’12 C. nodosa L2 462114 3082872 8.8 Oct’12 C. prolifera L1 463559 3089684 13.7 Nov’11, Oct’12 C. prolifera L2 463105 3089320 14.6 Nov’11, Oct’12

Each habitat (i.e. C. nodosa vs. C. prolifera-dominated beds) was sampled at each of two localities, where n=10, randomly allocated, samples were collected by

SCUBA divers, using a 20x20 cm quadrat. Collections were performed cutting the seagrass/seaweed immediately above the sediment surface, keeping the vegetation with

5 the associated epifauna in unbleached woven cotton bags (Brearley et al., 2008; Gartner et al., 2013). Sampling was repeated twice (November 2011 and October 2012) to merely assess whether patterns in the diversity, abundance and structure of epifaunal assemblages between beds dominated by C. nodosa and C. prolifera were temporally consistent.

Labelled samples were preserved in a freezer (-20 ºC) until processed. In the laboratory, samples collected were initially defrosted and subsequently sieved through a

500 m mesh to retain macrofaunal organisms. Specimens were sorted and counted into different taxonomic groups under a binocular microscope and preserved in 70% ethanol.

Four main functional groups: Crustacea, , worms (including Annelida and

Sipuncula) and other fauna (Chelicerata, Chordata and Echinodermata) were considered. All organisms were identified to species level, whenever possible. In particular, amphipods were identified to the lower taxonomic resolution (species in most cases), because amphipods was the most abundant taxa and because of their importance as biological indicators of human-induced alterations (Sánchez-Jerez et al., 2000). The amount of vegetated biomass (wet weight) was obtained for each replicate to account for differences in the amount of habitat (vegetation) among samples.

2.2. Statistical analysis

2.2.1. Univariate analysis

Differences in the abundance and species density (the number of species per area) of the dominant groups (here, Crustacea, Mollusca, Amphipoda, worms and other fauna) between habitats, localities within habitats and times were tested using a 3-way

ANCOVA, which incorporated the factors: ‛Habitat’ (fixed with 2 levels: C. nodosa vs.

C. prolifera), ‛Locality’ (random and nested within ‛Habitat’, 2 levels: L1 and L2), and

6 ‛Time’ (fixed with 2 levels: Nov’11 vs. Oct’12); ‛Leaf biomass’ was included as a covariate to account for differences in the amount of available habitat for epifauna among samples. Data were square root transformed prior to analyses, and analyses based on Euclidean distances (Anderson, 2001a). For each ANCOVA, we estimated the relative contribution of each factor to explain differences in the response variable through calculation of their corresponding variance components.

2.2.2. Multivariate analysis

Differences in the multivariate structure (what includes the abundance and composition) of assemblages between habitats (C. nodosa vs. C. prolifera) were visualized through a non-metric multidimensional scaling (nm-MDS) ordination plot, based on Bray-Curtis similarities. The significance of these multivariate differences were tested by a 3-way PERMANOVA (Anderson, 2001b), using ‛Time’, ‛Habitat’ and

‛Locality’ as factors, following the same design outlined above. The leaf biomass of each replicate was, again, included as a covariate. PERMANOVA data were square root transformed prior to analyses, and analyses were based on Euclidean distances. The individual contribution of each amphipod species to the dissimilarity between habitats

(C. nodosa vs. C. prolifera) was calculated by the SIMPER routine, based on Bray-

Curtis similarities.

All uni- and multivariate procedures were carried out by means of the PRIMER

6.0 & PERMANOVA statistical package.

7 3. Results

3.1. Epifaunal assemblages

A total of 4655 epifaunal individuals, belonging to 105 taxa (Appendix 1), were counted within the four dominant functional groups: crustaceans (3594 individuals), mollusks (777), worms (138) and other fauna (146). The abundance of crustaceans, which proved to be the dominant group (representing the 77.2 % of the total abundance), was significantly larger in Caulerpa prolifera-dominated beds (1792.5 ±

181.18 ind. m-2, mean  SE) than in Cymodocea nodosa meadows (562.5 ± 81.92 ind. m-2) at both sampling times (Fig. 1; 3-way ANCOVA: ‘Habitat’, P=0.0002, Table 2).

The species density of crustaceans was also larger in C. prolifera-dominated beds than in C. nodosa meadows (12.03 ± 0.52 vs. 5.8 ± 0.47 sp. 0.04 m-2, respectively) (Fig. 2;

3-way ANCOVA: ‘Habitat’, P=0.0002, Table 2). The abundance of mollusks was, again, significantly larger in C. prolifera-dominated beds (415.63 ± 71.4 ind. m-2) than in C. nodosa meadows (70 ± 15.14 ind. m-2) (Fig. 1; 3-way ANCOVA: ‘Habitat’,

P=0.0002, Table 2), as well as the species density of mollusks (3.45 ± 0.23 vs. 1.6 ± 0.2 sp. 0.04 m-2, respectively) (Fig. 2; 3-way ANCOVA: ‘Habitat’, P=0.0002, Table 2).

Worms showed a different pattern between sampling times, but abundance and species density were, on average, larger in C. prolifera-dominated beds (80 ± 16.32 ind. m-2 and

1.33 ± 0.09 sp. 0.04 m-2, respectively) than in C. nodosa meadows (26.25 ± 6.39 ind. m-

2 and 0.65 ± 0.07 sp. 0.04 m-2) (Fig. 1 and 2; 3-way ANCOVA: ‘Habitat’, P=0.0002,

Table 2). Finally, other faunal individuals were more abundant in C. prolifera- dominated beds (70 ± 20.16 ind. m-2) than in C. nodosa meadows (70 ± 15.14 ind. m-2), but without significant differences (Fig. 1; 3-way ANCOVA: ‘Habitat’, P=0.6590,

Table 2). The species density of other fauna (0.7 ± 0.12 vs. 0.45 ± 0.35 sp. 0.04 m-2,

8 respectively) (Fig. 2) was not significant either (3-way ANCOVA: ‘Habitat’, P=1.0000,

Table 2).

2500 2500 a) b) Crustacea 2000 2000 Mollusca Worms 1500 1500 Other fauna

)

-2 1000 1000

500 500

200 200

150 150

Abundance (ind. m (ind. Abundance 100 100

50 50

0 0 C. nodosa C. prolifera C. nodosa C. prolifera

Figure 1. Mean abundance (ind. m-2  SE) of the 4 functional groups at each habitat in (a)

November 2011 and (b) October 2012.

14 14 a) b) Crustacea Mollusca 12 12 Worms

)

-2 Other fauna 10 10

8 8

6 6

4 4

Species density (sp. 0.04 m 0.04 (sp. density Species 2 2

0 0 C. nodosa C. prolifera C. nodosa C. prolifera

Figure 2. Mean species density (number of species ± SE) of the 4 functional groups at each habitat in (a) November 2011 and (b) October 2012.

9

Table 2. Results of 3-way ANCOVAs testing for differences between habitats, times and localities within habitats, for the abundance and species density of each functional group. *Significant difference at P<0.05. The amount of variance (%CV) explained by each factor is included.

CRUSTACEA Abundance Species density

df MS F P %CV MS F P %CV

Covariate = Leaf biomass 1 903.86 2.1887 0.1462 5.35% 1.74 1.0657 0.3052 1.52% Time 1 75.89 0.0460 0.8266 0% 0.13 0.0357 0.8410 0% Habitat 1 7085.30 5.9660 0.0002* 30.42% 23.86 4.8950 0.0002* 33.16% Locality(Ha) 2 1574.70 24.2620 0.0002 18.76% 6.49 38.1210 0.0002 23.33% TixHa 1 80.91 0.0617 0.8100 0% 0.60 0.2138 0.6791 0% TixLo(Ha) 2 1642.10 25.3000 0.0002 28.09% 3.52 20.6610 0.0002 24.87% Residual 71 64.90 17.39% 0.17 17.12%

Total 79

MOLLUSCA Abundance Species density

df MS F P %CV MS F P %CV

Covariate = Leaf biomass 1 386.81 3.3939 0.0762 4.7916 0.97 0.7060 0.3910 0.0000 Time 1 2262.20 7.8276 0.1048 19.3216 4.94 4.4910 0.1550 14.5368 Habitat 1 1292.50 3.9539 0.0002* 14.7938 8.75 2.1964 0.0002* 17.7108 Locality(Ha) 2 433.26 23.6670 0.0002 11.8233 5.29 26.3780 0.0002 22.3086 TixHa 1 1472.90 6.7506 0.1099 24.6531 2.03 2.6053 0.2347 13.2611 TixLo(Ha) 2 271.08 14.8070 0.0002 13.5152 0.93 4.6486 0.0108 12.3886 Residual 71 18.31 11.1013 0.20 19.7949

Total 79

WORMS Abundance Species density

df MS F P %CV MS F P %CV

Covariate = Leaf biomass 1 8.46 0.3701 0.5430 0% 0.04 0.1204 0.7252 0% Time 1 53.98 0.3520 0.5856 0% 0.09 0.0520 0.8190 0% Habitat 1 310.50 8.6372 0.0002* 20.06% 3.74 9.7138 0.0002* 24.00% Locality(Ha) 2 42.50 2.5050 0.0854 7.46% 0.39 1.1012 0.3414 3.04% TixHa 1 254.03 2.0613 0.2672 20.24% 1.66 0.9854 0.4229 0% TixLo(Ha) 2 151.36 8.9221 0.0004 25.06% 2.03 5.6634 0.0042 30.23% Residual 71 16.96 27.18% 0.36 42.73%

Total 79

OTHER FAUNA Abundance Species density

df MS F P %CV MS F P %CV

Covariate = Leaf biomass 1 180.77 6.1752 0.0182 8.46% 0.0024 0.0045 0.9442 0% Time 1 474.15 11.0950 0.0758 21.43% 3.73 3.1454 0.2040 15.22% Habitat 1 0.63 0.0114 0.6590 0% 0.08 0.0603 1.0000 0% Locality(Ha) 2 68.69 3.9334 0.0182 9.85% 1.75 10.1600 0.0006 15.99% TixHa 1 264.64 7.4973 0.1146 24.99% 4.07 4.4363 0.1566 27.08% TixLo(Ha) 2 40.02 2.2915 0.1050 9.57% 1.11 6.4597 0.0024 18.08% Residual 71 17.46 25.70% 0.17 23.62%

Total 79

10

The two-dimensional MDS plot showed a separation of epifaunal assemblages by habitats and times: epifauna associated with Cymodocea nodosa meadows are in the left-hand side of the ordination space, while epifauna inhabiting Caulerpa prolifera- dominated beds are in the right-hand side of the plot. In addition, samples corresponding to November 2011 are in the top side, whereas those corresponding to

October 2012 are in the bottom side of the plot (Fig. 3). This multivariate response, however, was only statistically significant between habitats (3-way PERMANOVA:

‘Habitat’, P=0.0002; Table 3).

Figure 3. Two-dimensional MDS plot showing similarities in the epifaunal assemblage structure between habitats and times. Each symbol corresponds to a sampling locality within each habitat. Triangles: C. nodosa, circles: C. prolifera. Filled symbols: Nov’11, unfilled symbols: Oct’12.

11

Table 3. Results of 3-way PERMANOVA testing for differences between habitats, times and localities within habitats, for the epifaunal assemblage structure. *Significant differences for

P<0.05. The amount of variance (%CV) explained by each factor is included.

df MS F P %CV

Covariate = Leaf biomass 1 5212.7 3.0345 0.001 5.97% Time 1 13002 2.6701 0.1278 13.67% Habitat 1 11108 2.4333 0.0002* 13.41% Locality(Ha) 2 5987.8 13.656 0.0002 15.05% TixHa 1 7014.8 1.8769 0.2272 13.87% TixLo(Ha) 2 4610.3 10.515 0.0002 19.12% Residual 71 438.47 18.92%

Total 79

3.2. Amphipod assemblages

A total of 37 amphipod species, belonging to 16 families, were recorded

(Appendix 1). The abundance of amphipods constituted ca. 70% of crustaceans for the overall study and was significantly larger in Caulerpa prolifera-dominated beds

(1248.13 ± 136.83 ind. m-2, mean ± SE) than in Cymodocea nodosa meadows (396.88 ±

77.36 ind. m-2) at both sampling times (Fig. 4a; 3-way ANCOVA: ‘Habitat’, P=0.0002,

Table 4). A similar pattern was found for amphipod species density (7.05 ± 0.47 vs. 4.25

± 0.38 sp. 0.04 m-2, respectively; Fig. 4b), but differences were not statistically significant (3-way ANCOVA: ‘Habitat’, P=0.3406, Table 4).

12

2000 10 a) b) Nov'11 Oct'12

)

-2 8 1500

)

-2

6

1000

4

Abundance (ind. m (ind. Abundance 500 2

Species density (sp. 0.04 m 0.04 (sp. density Species

0 0 C. nodosa C. prolifera C. nodosa C. prolifera

Figure 4. (a) Mean abundance (ind. m-2  SE) and (b) mean species density (number of species

 SE) of amphipods at each habitat and time.

Table 4. Results of 3-way ANCOVA testing for differences between habitats, times and localities within habitats, for the total abundance and species density of amphipods. *Significant difference at P<0.05. The amount of variance (%CV) explained by each factor is included.

Total abundance Total species density df MS F P %CV MS F P %CV Cova riate = Leaf biomass 1 1550.8 4.5936 0.0396 9.42% 14.06 0.3522 0.5544 0% Time 1 994.15 0.7567 0.4326 0% 5.54 0.0705 0.8078 0% Habitat 1 4804.3 4.8642 0.0002* 27.43% 196.15 1.6149 0.3406 17.65% Locality(Ha) 2 1312.5 28.8590 0.0002 19.27% 162.20 49.5220 0.0002 31.39% TixHa 1 12.32 0.0123 0.9186 0% 0.02 0.0004 0.9896 0% TixLo(Ha) 2 1253.2 27.5540 0.0002 27.55% 74.69 22.8030 0.0002 30.82% Residual 71 45.48 16.32% 3.28 20.14%

Total 79

The two-dimensional MDS plot showed a clear segregation of amphipod assemblages mainly by habitat: amphipods associated with Cymodocea nodosa meadows are in the left-hand side of the plot, while amphipods associated with

Caulerpa prolifera-dominated beds are in the right-hand side. Samples collected in

November 2011 were more dissimilar to each other than those obtained in October 2012

13

(Fig. 5). However, the structure of amphipod assemblages was only statistically significant between habitats (3-way PERMANOVA: ‘Habitat’, P=0.0002, Table 5).

Figure 5. Two-dimensional MDS plot showing similarities in the amphipod assemblage structure between habitats and times. Each symbol corresponds to a sampling locality within habitats. Triangles: C. nodosa, circles: C. prolifera. Filled symbols: Nov’11, unfilled symbols:

Oct’12.

Table 5. Results of 3-way PERMANOVA testing for differences between habitats, times and locations within habitats, for the amphipod assemblage structure. *Significant differences for

P<0.05. The amount of variance (%CV) explained by each factor is included.

df MS F P %CV Covariate = Leaf biomass 1 1528.4 1.2753 0.2314 2.97% Time 1 4796.5 1.4492 0.3056 9.45% Habitat 1 8107.8 2.4173 0.0002* 18.48% Locality(Ha) 2 4431.1 19.278 0.0002 21.18% TixHa 1 2188.6 0.86856 0.4874 0% TixLo(Ha) 2 3125.6 13.598 0.0002 25.76% Residual 71 229.86 22.15% Total 79

14

The amphipod species which most contributed to dissimilarities between habitats were: Microdeutopus stationis, Dexamine spinosa, Aora spinicornis, Mantacaprella macaronensis, Pseudoprotella phasma, Ampithoe ramondi, Ischyrocerus inexpectatus and Apherusa bispinosa. These species made up ca. 60% of the total abundance of amphipods. Amphipod assemblages showed a clear segregation, with different species contributing to the dissimilarity between habitats. For example, the abundance of M. stationis, D. spinosa and A. spinicornis was significantly larger in C. prolifera- dominated beds (Fig. 6a, b, c; 3-way ANCOVA: ‘Habitat’, P<0.05, Table 6), while the new species of caprellid M. macaronensis (Fig. 7; Vázquez-Luis et al., 2013; in revision) significantly dominated in C. nodosa meadows (Fig. 6d; 3-way ANCOVA:

‘Habitat’, P=0.0002, Table 6). The other caprellid species, P. phasma, also showed larger abundances in C. nodosa meadows, although the difference with respect to C. prolifera-dominated beds was not statistically significant (Fig. 6e; 3-way ANCOVA:

‘Habitat’, P=0.6612, Table 6). The gammarid A. ramondi was found in both habitats, with larger abundances in C. prolifera-dominated beds, but without significant differences (Fig. 6f; 3-way ANCOVA: ‘Habitat’, P=0.6800, Table 6). Finally, I. inexpectatus and A. bispinosa were more abundant in C. prolifera-dominated beds, but no significant differences were detected between habitats, probably masked by the high variability between localities (Fig. 6g, h; 3-way ANCOVA: ‘Habitat’, P>0.05, Table 6).

15

350 a) Microdeutopus stationis b) Dexamine spinosa 300 300

250 200

200 100

50 150 40

100 30

20 50 10

0 0

350

c) Aora spinicornis 300 d) Mantacaprella macaronensis 300

250 200

200 100

50 150 40

100 30

) 20 -2 50 10

0 0

350 e) Pseudoprotella phasma f) Ampithoe ramondi

300 300

250

Abundance (ind. m (ind. Abundance 200 200

100 150

75 100 50

50 25

0 0

g) Ischyrocerus inexpectatus h) Apherusa bispinosa 300 300

200 200

100 100

20 50

40 15 30 10 20 5 10

0 0 C. nodosa C. prolifera C. nodosa C. prolifera

Figure 6. Mean abundance (ind. m-2  SE) of the most important amphipod species at each habitat.

16

Table 6. Results of 3-way ANCOVAs testing for differences between habitats, times and localities within habitats, for the abundance of the most important amphipod species. *Significant differences for P<0.05. The amount of variance (%CV) explained by each factor is included.

Microdeutopus stationis Dexamine spinosa

df MS F P %CV MS F P %CV

Covariate = Leaf biomass 1 325.79 1.1317 0.2856 2.07% 606.04 18.6590 0.0008 9.61% Time 1 563.44 1.8731 0.2866 8.20% 1313.80 17.8540 0.0500 21.20% Habitat 1 2414.9 2.7502 0.0002* 21.68% 1183.10 16.9750 0.0002* 21.98% Locality(Habitat) 2 1173 51.703 0.0002 22.87% 88.29 5.6029 0.0056 6.84% TimexHabitat 1 581.46 2.7391 0.2214 15.53% 388.08 6.6477 0.1155 17.49% TimexLo(Habitat) 2 262.44 11.568 0.0002 15.29% 69.65 4.4201 0.0150 8.63% Residual 71 22.69 14.36% 15.76 14.25%

Total 79

Aora spinicornis Mantacaprella macaronensis

df MS F P %CV MS F P %CV

Covariate = Leaf biomass 1 119.41 2.2410 0.1502 4.29% 0.0065 0.0001 0.9942 0% Time 1 277.33 0.6036 0.5068 0% 368.48 0.9490 0.4310 0% Habitat 1 1436.90 10.5870 0.0002* 31.24% 1126.80 2.9057 0.0002* 26.20% Locality(Habitat) 2 176.93 10.8940 0.0002 13.38% 518.80 66.7480 0.0002 26.57% TimexHabitat 1 160.31 0.4498 0.5641 0% 106.09 0.3643 0.6086 0% TimexLo(Habitat) 2 446.38 27.4850 0.0002 32.07% 366.21 47.1160 0.0002 32.59% Residual 71 16.24 19.02% 7.77 14.65%

Total 79

Pseudoprotella phasma Ampithoe ramondi

df MS F P %CV MS F P %CV

Covariate = Leaf biomass 1 18.06 0.0821 0.7754 0% 37.21 2.0019 0.1674 3.75% Time 1 259.49 0.7038 0.4774 0% 275.43 2.2711 0.2426 16.18% Habitat 1 28.76 0.0433 0.6612 0% 24.28 0.7197 0.6800 0% Locality(Habitat) 2 887.31 43.9170 0.0002 38.93% 41.30 3.5043 0.0382 9.44% TimexHabitat 1 27.01 0.0995 0.7282 0% 168.45 1.7604 0.2983 17.77% TimexLo(Habitat) 2 337.75 16.7170 0.0002 34.50% 117.89 10.0040 0.0006 26.21% Residual 71 20.20 26.56% 11.79 26.66%

Total 79

Ischyrocerus inexpectatus Apherusa bispinosa

df MS F P %CV MS F P %CV

Covariate = Leaf biomass 1 80.94 0.4627 0.4382 0% 80.94 0.4627 0.4590 0% Time 1 574.97 0.8736 0.4360 0% 574.97 0.8736 0.4336 0% Habitat 1 789.99 1.6073 0.2470 14.13% 789.99 1.6073 0.2540 14.13% Locality(Habitat) 2 649.69 19.8570 0.0002 24.76% 649.69 19.8570 0.0002 24.76% TimexHabitat 1 369.51 0.7336 0.4693 0% 369.51 0.7336 0.4709 0% TimexLo(Habitat) 2 628.32 19.2040 0.0002 35.63% 628.32 19.2040 0.0002 35.63% Residual 71 32.72 25.49% 32.72 25.49%

Total 79

17

Figure 7. Mantacaprella macaronensis n. sp. Lateral view of holotype male (4.5 mm) and paratype female (2.7 mm). Scale bar: 1 mm.

18 4. Discussion

4.1. Overall epifaunal assemblage response

Our results have indicated clear differences in the multivariate structure, in terms of abundance and diversity (here quantified through the species density), of epifaunal assemblages between habitats dominated by the seagrass Cymodocea nodosa and the green seaweed Caulerpa prolifera, and patterns of differences have been consistently through times. Larger abundances and species densities were found, unexpectedly, in C. prolifera-dominated beds, since caulerpenyne seems to reduce macrophyte palatability and act as deterrent against some herbivore species (Erickson et al., 2006). In accordance with our results, previous studies have demonstrated that seabeds dominated by Caulerpa prolifera may particularly benefit crustacean assemblages (Sánchez-

Moyano et al., 2007a), revealing the importance of this vegetated habitat for the maintenance of the biodiversity in coastal areas under considerable human impacts

(Sánchez-Moyano et al., 2001b). A previous study conducted in the Canaries also recorded higher macrofaunal diversity in mixed bottoms of C. prolifera and C. nodosa than in mono-specific C. nodosa meadows (Monterroso et al., 2012). Differences in the structure, abundance and diversity of epifaunal assemblages may be due to changes in the structural complexity of the habitat (e.g. plant identity, plant morphology, floral and faunal epiphytes) (Virnstein and Howard, 1987; Taylor and Cole, 1994; Bologna, 1999), which plays an important role as space available for shelter against predators; but also due to changes in the hydrodynamic properties of the habitat. In the Mediterranean,

Hendriks et al. (2010) demonstrated that, seasonally, Caulerpa species are able to attenuate water flow, trap particles and protect the sediment from erosion even better than seagrasses (particularly C. prolifera vs. C. nodosa), thus seabeds constituted by

19 Caulerpa spp. might affect the associated fauna compared to seagrass meadows; favoring macrofaunal assemblages mainly dominated by crustaceans and polychaetes

(Hendriks et al., 2010; Monterroso et al., 2012).

Differences within invertebrate assemblages are expected between different types (identities) of vegetation within the same geographical and environmental context

(Sirota and Hovel, 2006). Low epifaunal abundances associated with C. nodosa meadows may be explained by space limitation, so the architecture of C. nodosa would be less important for fauna that are limited by space in comparison to other seagrasses, such as Posidonia sinuosa and Amphibolis griffithii, which have a higher leaf surface area and algal epiphyte biomass (Gartner et al., 2013). Epifaunal assemblages are also subjected to substrate competitive exclusion due to source limitation (Duffy and

Harvilicz, 2001) and to fish predatory pressure. Seagrasses provide a paramount role as habitat for nearshore fish assemblages (Espino et al., 2011a). In the study region, C. nodosa meadows play a ‘nursery’ role for the early stages of numerous fish species

(Espino et al., 2011a, 2011b). The abundance of fishes is ca. 3-4 times larger in C. nodosa than in C. prolifera dominated beds (unpublished data). Epifaunal organisms, particularly crustaceans, are the main constituent of diets of seagrass-associated fishes

(Yamada et al., 2010; Horinouchi et al., 2012). Hence, it is worth noting that the contrasting abundance patterns of epifaunal and fish assemblages between C. nodosa and C. prolifera bottoms might fits a classical ‘predation’ model, where a large abundance of predators (here, fishes) remove large quantities of prey (here, epifauna) and so explain decreasing abundance of prey in such habitats (here, C. nodosa seagrass meadows) (Verdiell-Cubedo et al., 2007).

20

4.2. Amphipod assemblage response

The amphipod assemblage structure has significantly differed between habitats at both sampling times, showing a mean abundance of amphipods ca. 3 times larger in

Caulerpa prolifera-dominated beds (1248.13 ± 136.83 ind. m-2, mean ± SE) than in

Cymodocea nodosa meadows (396.88 ± 77.36 ind. m-2). Our results of amphipods abundance do not agree, for example, with those reported by Vázquez-Luis et al. (2009) for the same habitats (313.89 ± 75.63 ind. m-2 in C. prolifera and 494.44 ± 160.17 ind. m-2 in C. nodosa, mean ± SE). Regarding the diversity of amphipods, in C. nodosa seagrass meadows at Gran Canaria we have recorded values of 16 amphipod species in

November 2011 and 17 in October 2012, which are comparable or even lower than the number of amphipod species reported by several studies carried out in the

Mediterranean Sea and the adjacent Atlantic coasts in C. nodosa meadows (28 species,

Sánchez-Jerez et al., 1999; 13 species in September and 21 in March, Vázquez-Luis et al., 2009). On vegetated bottoms dominated by C. prolifera, a total of 27 and 20 amphipod species (in November 2011 and October 2012, respectively) were identified, which contrast with the 17 amphipod species recorded by Sánchez-Moyano et al. (2007) and values of 6 and 18 species reported by Vázquez-Luis et al. (2009) for the same habitat (in September and March, respectively). The variation within the total number of amphipod species among studies show a more diverse epifaunal community in C. prolifera-dominated beds at Gran Canaria.

Several authors have stated that amphipods are able to actively select their host habitat (Hay et al., 1990; Poore, 2005; Poore and Hill, 2006), a fact that is related to differences on vegetation palatability and food preferences by herbivores (Ortega et al.,

2010). However, although the active selection appears important, it is not sufficient by itself to explain differential patterns of epifaunal distribution (Virnstein and Howard,

21

1987). The presence of diverse amphipods on plant species may result from ecological processes unrelated to herbivore preferences or the quality of that host for growth and survival, but from the variation in the risk of predation among hosts (Poore, 2005). As reported above, the susceptibility of amphipods to fish predation commonly varies across algal species, usually decreasing with increased structural complexity of the host or with the presence of secondary metabolites that are deterrent to omnivorous fish

(Poore, 2005; Verdiell-Cubedo et al., 2007; Vázquez-Luis et al., 2010).

In the current study, some species seem to show a preference for specific habitats and, in overall, it is possible to distinguish gammarid species associated with C. prolifera-dominated beds, while caprellids are associated with C. nodosa meadows.

Within gammarids, individuals belonging to the family Aoridae (here, Aora spinicornis and Microdeutopus stationis) have been exclusively found in C. prolifera-dominated beds. This outcome contrasts with previous records; for example, A. spinicornis has been found among hydroids, phanerogams and algae, and on sandy bottoms as well

(Ruffo, 1982); whilst M. stationis has been almost exclusively found on fine sand, particularly among the phanerogams Cymodocea and Posidonia, with some records on coralligenous habitats (Ruffo, 1998). However, other authors found also larger abundances of Microdeutopus spp. in Caulerpa beds and on rocky habitats (Roberts and

Poore, 2005; Vázquez-Luis et al., 2008, 2009), with preference for low hydrodynamic regimes and high sedimentation rates (Conradi et al., 1997; Guerra-García and García-

Gómez, 2005). Other species significantly more abundant in C. prolifera-dominated beds was the free-living, herbivore Dexamine spinosa, which is very common within algal canopies within the shallow subtidal (Lincoln, 1979; Ruffo, 1982). Apherusa bispinosa and Ischyrocerus inexpectatus were also collected in higher abundance in C. prolifera-dominated beds. Consistent with our results, Farlin et al. (2010) reported that

22 ischyrocerids, such as I. inexpectatus, tend to feed more on algae than on seagrasses. As the previous gammarids, Ampithoe ramondi was, again, more abundant in C. prolifera- dominated beds than in C. nodosa meadows, although differences were not so great.

Ampithoids are, cosmopolitan, herbivorous amphipods, which usually occur in shallow subtidal zones amongst native seaweeds and seagrasses (Lincoln, 1979; Ruffo, 1982;

Poore, 2005; Vázquez-Luis et al., 2008, 2009), tending to feed more on seagrasses

(Farlin et al., 2010). The caprellid Pseudoprotella phasma has been mostly found inhabiting C. nodosa meadows, although this species might also be found among algae, but rarely associated with hydroids (Ruffo, 1993).

Finally, it is important to highlight the new genus, new species, of caprellid,

Mantacaprella macaronensis, which show a clear preference on C. nodosa seagrass meadows, but also occurring in C. prolifera-dominated beds. This species was firstly recorded in Cape Verde, in natural rocky and artificial habitats (shipwrecks), in 2009; and together with the results of the current study, M. macaronensis has been recently described by Vázquez-Luis et al. (in revision). The relatively high abundances found in the Canary Islands and Cape Verde reflects the lack of detailed studies on benthic fauna in the region, namely on amphipods, and therefore this new species is expected to be also present in other islands of the Macaronesian region.

In conclusion, our study shows that Caulerpa prolifera-dominated beds have a more abundant and diverse epifaunal assemblage, which significantly differs from

Cymodocea nodosa meadows and is temporally consistent. According to the biodiversity related to Cymodocea nodosa seagrass meadows, this study has been used as an important tool for the taxonomical and ecological description of the new genus, new species, of caprellid, since Mantacaprella macaronensis has resulted one of the dominant amphipods inhabiting these meadows. This reflects the lack of knowledge on

23

Macaronesian invertebrates, like amphipods, and the need of further taxonomical studies to better characterise the biodiversity of this region and to design adequate programmes of management and conservation.

Acknowledgements

This study was financially supported by the UE project “Changes in submerged vegetation: assessing how ecosystems services shift from frondose to depauperate systems dominated by opportunistic seaweeds (ECOSERVEG)”. We acknowledge T.

Sánchez and F. Espino for their help during fieldwork. Special thanks to J.M. Guerra-

García and his team for their welcome at the Marine Biology’s lab (Universidad de

Sevilla).

References

Anderson, M.J., 2001a. A new method for non-parametric multivariate analysis of variance. Austral Ecology 26, 32-46.

Anderson, M.J., 2001b. Permutation tests for univariate or multivariate analysis of variance and regression. Canadian Journal of Fisheries and Aquatic Sciences 58, 626-639.

Barberá, C., Tuya, F., Boyra, A., Sanchez-Jerez, P., Blanch, I., Haroun, R.J., 2005. Spatial variation in the structural parameters of Cymodocea nodosa seagrass meadows in the Canary Islands: A multiscaled approach. Botanica Marina 48, 122- 126.

Box, A., Sureda, A., Tauler, P., Terrados, J., Marbà, N., Pons, A., Deudero, S., 2010. Seasonality of caulerpenyne content in native Caulerpa prolifera and invasive C. taxifolia and C. racemosa var. cylindracea in the western Mediterranean Sea. Botanica Marina 53, 367-375.

Brearley, A., Kendrick, A.J., Walker, D., 2008. How does burrowing by the isopod Limnoria agrostisa (Crustacea: Limnoriidae) affect the leaf canopy of the southern Australian seagrass Amphibolis griffithii? Marine Biology 156, 65-77.

24 Conradi, M., López-González, P.J., García-Gómez, C., 1997. The amphipod community as a bioindicator in Algeciras Bay (Southern Iberian Peninsula) based on a spatio- temporal distribution. Marine Ecology 18 (2), 97-111.

Costanza, R., d’Arge, R., de Groot, R., Farber, S., Grasso, M., Hannon, B., Limburg, K., Naeem, S., O’Neill, R.V., Paruelo, J., Raskin, R.G., Sutton, P., van den Belt, M., 1997. The value of the world’s ecosystem services and natural capital. Nature 387, 253-260.

Duarte, C.M., 2000. Marine biodiversity and ecosystem services: An elusive link. Journal of Experimental Marine Biology and Ecology 250, 117-131.

Duarte, C.M., 2002. The future of seagrass meadows. Environmental Conservation 29 (2), 192-206.

Duffy, J.E., Hay, M.E., 2000. Strong impacts of grazing amphipods on the organization of a benthic community. Ecological Monographs 70, 237-263.

Duffy, J.E., Harvilicz, A.M., 2001. Species-specific impacts of grazing amphipods in an eelgrass-bed community. Marine Ecology Progress Series 223, 201-211.

Duffy, J.E., 2006. Biodiversity and the functioning of seagrass ecosystems. Marine Ecology Progress Series 311, 233-250.

Erickson, A.A., Paul, V.J., Van Alstyne, K.L., Kwiatkowski, L.M., 2006. Palatability of macroalgae that use different types of chemical defenses. Journal of Chemical Ecology 32, 1883-1895.

Espino, F., Tuya, F., Brito, A., Haroun, R., 2011a. Ichthyofauna associated with Cymodocea nodosa meadows in the Canarian Archipelago (central eastern Atlantic): Community structure and nursery role. Ciencias Marinas 37 (2), 157- 174.

Espino, F., Tuya, F., Brito, A., Haroun, R., 2011b. Variabilidad espacial en la estructura de la ictiofauna asociada a praderas de Cymodocea nodosa en las Islas Canarias, Atlántico nororiental subtropical. Revista de Biología Marina y Oceanografía 46 (3), 391-403.

Farlin, J.P., Lewis, L.S., Anderson, T.W., Lai, C.T., 2010. Functional diversity in amphipods revealed by stable isotopes in an eelgrass ecosystem. Marine Ecology Progress Series 420, 277-281.

Gartner, A., Tuya, F., Lavery, P.S., McMahon, K., 2013. Habitat preferences of macroinvertebrate fauna among seagrasses with varying structural forms. Journal of Experimental Marine Biology and Ecology 439, 143-151.

Guerra-García, J.M., García-Gómez, J.C., 2005. Assessing pollution levels in sediments of a harbour with two opposing entrances. Environmental implications. Journal of Environmental Management 77, 1-11.

25

Harlin, M.M., 1980. Seagrass Epiphytes. In: McRoy, P., Phillips, R. (Eds.), Handbook of Seagrass Biology: An ecosystem perspective. Garland STPM Press, New York, pp. 117-151.

Haroun, R., Gil-Rodríguez, M.C., Wildpret de la Torre, W., 2003. Plantas Marinas de las Islas Canarias. Canseco Editores, 319 p.

Hay, M.E., Duffy, J.E., Fenical, W., 1990. Host-plant specialization decreases predation on a marine amphipod: An herbivore in plant’s clothing. Ecology 71 (2), 733-743.

Hendriks, I.E., Bouma, T.J., Morris, E.P., Duarte, C.M., 2010. Effects of seagrasses and algae of the Caulerpa family on hydrodynamics and particle-trapping rates. Marine Biology 157, 473-481.

Horinouchi, M., Tongnunui, P., Furumitsu, K., Nakamura, Y., Kanou, K., Yamaguchi, A., Okamoto, K., Sano, M., 2012. Food habits of small fishes in seagrass habitats in Trang, southern Thailand. Fisheries Science 78, 577-587.

Hughes, A.R., Williams, S.L., Duarte, C.M., Heck, K.L., Waycott, M., 2009. Associations of concern: Declining seagrasses and threatened dependent species. Frontiers in Ecology and the Environment 7 (5), 242-246.

Jung, V., Thibaut, T., Meinesz, A., Pohnert, G. (2002). Comparison of the wound- activated transformation of caulerpenyne by invasive and noninvasive Caulerpa species of the Mediterranean. Journal of Chemical Ecology 28 (10), 2091–2105.

Lincoln, R.J., 1979. British Marine Amphipoda: Gammaridea. British Museum (Natural History), 671 p.

Martínez-Samper, J., 2011. Análisis espacio-temporal de las praderas de Cymodocea nodosa (Ucria) Ascherson en la isla de Gran Canaria. Master thesis, Universidad de Las Palmas de Gran Canaria.

Meinesz, A., 1999. From the discovery of the Alga in Monaco to its arrival in France. In: Meinesz, A. (Eds.), Killer Algae. The University of Chicago Press, Chicago, pp. 1-22.

Monterroso, O., Riera, R., Núñez, J., 2012. Subtidal soft-bottom macroinvertebrate communities of the Canary Islands. An ecological approach. Brazilian Journal of Oceanography 60 (1), 1-9.

Ortega, I., Díaz, Y.J., Martín, A., 2010. Feeding rates and food preferences of the amphipods present on macroalgae Ulva sp. and Padina sp. Zoologica baetica 21, 45-53.

Orth, R.J., Carruthers, T.J.B., Dennison, W.C., Duarte, C.M., Fourqurean, J.W., Heck Jr., K.L., Hughes, A.R., Kendrick, G.A., Kenworthy, W.J., Olyarnik, S., Short, F.T., Waycott, M., Williams, S., 2006. A global crisis for seagrass ecosystems. BioScience 56 (12), 987-996.

26

Pavón-Salas, N., Herrera, R., Hernández-Guerra, A., Haroun, R., 2000. Distributional pattern of seagrasses in the Canary Islands (Central-East Atlantic Ocean). Journal of Coastal Research 16 (2), 329-335.

Poore, A.G.B., 2005. Scales of dispersal among hosts in a herbivorous marine amphipod. Austral Ecology 30, 219-228.

Poore, A.G.B., Hill, N.A., 2006. Sources of variation in herbivore preference: among- individual and past diet effects on amphipod hosts choice. Marine Biology 149, 1403-1410.

Reyes, J., Sansón, M., Afonso-Carrillo, J., 1995. Distribution and reproductive phenology of the seagrass Cymodocea nodosa (Ucria) Ascherson in the Canary Islands. Aquatic Botany 50, 171-180.

Roberts, D.A., Poore, A.G.B., 2005. Habitat configuration affects colonization of epifauna in a marine algal bed. Biological Conservation 127, 18-26.

Ruffo, S., 1982. The Amphipoda of the Mediterranean. Part 1: Gammaridea (Acanthonotozomatidae to Gammaridae). Mémoires de l’Institut Océanographique, Monaco 13, 364 p.

Ruffo, S., 1989. The Amphipoda of the Mediterranean. Part 2: Gammaridea (Haustoriidae to Lysianassidae). Mémoires de l’Institut Océanographique, Monaco 13, 221 p.

Ruffo, S., 1993. The Amphipoda of the Mediterranean. Part 3: Gammaridea (Melphidippidae to Talitridae), Ingolfiellidea, Caprellidea. Mémoires de l’Institut Océanographique, Monaco 13, 242 p.

Ruffo, S., 1998. The Amphipoda of the Mediterranean. Part 4. Mémoires de l’Institut Océanographique, Monaco 13, 150 p.

Sánchez-Jerez, P., Barberá Cebrián, C., Ramos Esplá, A.A., 1999. Comparison of the epifauna spatial distribution in , Cymodocea nodosa and unvegetated bottoms: Importance of meadow edges. Acta Oecologica, 20 (4), 391- 405.

Sánchez-Jerez, P., Barberá-Cebrián, C., Ramos-Esplá, A.A., 2000. Influence of the structure of Posidonia oceanica meadows modified by bottom trawling on crustacean assemblages: Comparison of amphipods and decapods. Scientia Marina 64 (3), 319-326.

Sánchez-Moyano, J.E., Estacio, F.J., García-Adiego, E.M., García-Gómez, J.C., 2001a. Effect of the vegetative cycle of Caulerpa prolifera on the spatio-temporal variation of invertebrate macrofauna. Aquatic Botany 70, 163-174.

Sánchez-Moyano, J.E., García-Adiego, E.M., Estacio, F.J., García-Gómez, J.C., 2001b. Influence of the density of Caulerpa prolifera (Chlorophyta) on the composition of

27

the macrofauna in a meadow in Algeciras Bay (Southern Spain). Ciencias Marinas 27 (1), 47-71.

Sánchez-Moyano, J.E., García-Asencio, I., García-Gómez, J.C., 2007. Effects of temporal variation of the seaweed Caulerpa prolifera cover on the associated crustacean community. Marine Ecology 28, 324-337.

Sirota, L., Hovel, K.A., 2006. Simulated eelgrass structural complexity: effects of shoot length, shoot density, and surface area on the epifaunal community of San Diego Bay, California, USA. Marine Ecology Progress Series 326, 115-131.

Smyrniotopoulos, V., Abatis, D., Tziveleka, L-A., Tsitsimpikou, C., Roussis, V., Loukis, A., Vagias, C., 2003. Acetylene sesquiterpenoid esters from the green alga Caulerpa prolifera. Journal of Natural Products 66, 21-24.

Taylor, R.B., Cole, R.G., 1994. Mobile epifauna on subtidal brown seaweeds in northeastern New Zealand. Marine Ecology Progress Series 115, 271-282.

Thomsen, M.S., Wernberg, T., Engelen, A.H., Tuya, F., Vanderklift, M.A. et al., 2012. A meta-analysis of seaweed impacts on seagrasses: Generalities and knowledge gaps. PloS ONE 7(1): e28595.

Tuya, F., Martín, J.A., Luque, A., 2006. Seasonal cycle of a Cymodocea nodosa seagrass meadow and of the associated ichthyofauna at Playa Dorada (Lanzarote, Canary Islands, eastern Atlantic). Ciencias Marinas 32 (4), 695-704.

Tuya, F., Hernandez-Zerpa, H., Espino, F., Haroun, R., 2013. Drastic decadal decline of the seagrass Cymodocea nodosa at Gran Canaria (eastern Atlantic): Interactions with the green algae Caulerpa prolifera. Aquatic Botany 105, 1-6.

Vázquez-Luis, M., Sanchez-Jerez, P., Bayle-Sempere, J.T., 2008. Changes in amphipod (Crustacea) assemblages associated with shallow-water algal habitats invaded by Caulerpa racemosa var. cylindracea in the western Mediterranean Sea. Marine Environmental Research 65, 416-426.

Vázquez-Luis, M., Sanchez-Jerez, P., Bayle-Sempere, J.T., 2009. Comparison between amphipod assemblages associated with Caulerpa racemosa var. cylindracea and those of other Mediterranean habitats on soft substrate. Estuarine, Coastal and Shelf Science 84, 161-170.

Vázquez-Luis, M., Sanchez-Jerez, P., Bayle-Sempere, J.T., 2010. Effects of Caulerpa racemosa var. cylindracea on prey availability: an experimental approach to predation of amphipods by Thalassoma pavo (Labridae). Hydrobiologia 654, 147- 154.

Vázquez-Luis, M., Guerra-García, J.M., Carvalho, S., Png-Gonzalez, L., 2013. A new genus and species of Caprellidae (Crustacea: Amphipoda) from Canary Islands and Cape Verde. Zootaxa (in revision)

28

Verdiell-Cubedo, D., Oliva-Paterna, F.J., Torralva-Forero, M., 2007. Fish assemblages associated with Cymodocea nodosa and Caulerpa prolifera meadows in the shallow areas of the Mar Menos coastal lagoon. Limnetica 26 (2), 341-350.

Virnstein, R.W., Howard, R.K., 1987. Motile epifauna of marine macrophytes in the Indian River Lagoon, Florida. II. Comparisons between drift algae and three species of seagrasses. Bulletin of Marine Science 41 (1), 13-26.

Waycott, M., Duarte, C.M., Carruthers, T.J.B., Orth, R.J., Dennison, W.C., Olyarnik, S., Calladine, A., Fourqurean, J.W., Heck Jr., K.L., Hughes, A.R., Kendrick, G., Kenworthy, W.J., Short, F.T., Williams, S.L., 2009. Accelerating loss of seagrasses across the globe threatens coastal ecosystems. PNAS 106, 12377-12381.

Yamada, K., Hori, M., Tanaka, Y., Hasegawa, N., Nakaoka, M., 2010. Contribution of different functional groups to the diet of major predatory fishes at a seagrass meadow in northeastern Japan. Estuarine, Coastal and Shelf Science 86, 71-82.

29

Appendix 1. Abundances (ind. per m-2  SE) of epifaunal organisms at each habitat and time. The total abundance and number of species are also included.

November 2011 October 2012 Functional group Group Species C. nodosa C. prolifera C. nodosa C. prolifera Worms Nematoda Calyptronema sp. - 11.25 ± 6.57 - - Worms Nematoda Enoplida sp. 1 - 13.75 ± 7.74 - - Worms Nematoda Unidentified - - - 3.75 ± 3.75 Worms Oligochaeta Unidentified - - - - Worms Polychaeta Aponuphis bilineata - 1.25 ± 1.25 - - Worms Polychaeta Platynereis dumerilii - 2.5 ± 1.44 - 21.25 ± 12.31 Worms Polychaeta Nereididae sp. 1 - 11.25 ± 5.54 - - Worms Polychaeta Exogone naidina - 2.5 ± 1.44 - - Worms Polychaeta Salvatoria sp. 1.25 ± 1.25 - - 1.25 ± 1.25 Worms Polychaeta Streptosyllis bidentata 5 ± 2.89 - - - Worms Polychaeta Syllis sp. 6.25 ± 4.73 - - - Worms Polychaeta Demonax brachychona - 6.25 ± 6.25 - - Worms Polychaeta Desdemona sp. - 2.5 ± 1.44 - - Worms Polychaeta Sabellidae sp. 1 - 1.25 ± 1.25 - - Worms Polychaeta Aonides oxycephala - 1.25 ± 1.25 - - Worms Polychaeta Polyophthalmus pictus 2.5 ± 2.5 76.25 ± 42.79 - - Worms Polychaeta Schroederella laubieri - 1.25 ± 1.25 - - Worms Sipunculidea sp. 1 - - - - Other fauna Pycnogonida Unidentified 27.5 ± 14.79 - 10 ± 5.4 48.75 ± 14.34 Other fauna Actinopterygii Opeatogenys cadenati - - 1.25 ± 1.25 - Other fauna Asteroidea Coscinasterias tenuispina - 2.5 ± 2.5 - - Other fauna Ophiuroidea Unidentified - 1.25 ± 1.25 1.25 ± 1.25 90 ± 54.04 Crustacea Copepoda Unidentified - 1.25 ± 1.25 15 ± 7.36 50 ± 35.18 Crustacea Cumacea Unidentified 2.5 ± 2.5 7.5 ± 4.79 - 6.25 ± 3.75 Crustacea Decapoda Caridea 2.5 ± 2.5 13.75 ± 5.91 - 217.5 ± 132.83 Crustacea Decapoda Galatheoidea - - - 13.75 ± 10.68 Crustacea Decapoda Paguroidea - 15 ± 4.56 - 95 ± 25.41

1

November 2011 October 2012 Functional group Group Species C. nodosa C. prolifera C. nodosa C. prolifera Crustacea Decapoda Brachyura 2.5 ± 1.44 11.25 ± 5.54 1.25 ± 1.25 21.25 ± 9.44 Crustacea Decapoda Larva - 2.5 ± 1.44 - 3.75 ± 2.39 Crustacea Isopoda sp. 1 1.25 ± 1.25 - 221.25 ± 106.29 2.5 ± 1.44 Crustacea Isopoda sp. 2 18.75 ± 11.25 3.75 ± 3.75 11.25 ± 8.0 - Crustacea Isopoda sp. 3 6.25 ± 6.25 - 5 ± 3.54 17.5 ± 10.9 Crustacea Isopoda sp. 4 - 6.25 ± 3.75 1.25 ± 1.25 10 ± 3.54 Crustacea Isopoda sp. 5 - 1.25 ± 1.25 - 6.25 ± 3.75 Crustacea Isopoda sp. 6 - - 1.25 ± 1.25 1.25 ± 1.25 Crustacea Tanaidacea Apseudes sp. - - - - Crustacea Tanaidacea Apseudes talpa - - - 5 ± 3.54 Crustacea Tanaidacea Leptochelia savignyi - - - 338.75 ± 148.32 Crustacea Tanaidacea Tanais dulongii - - 1.25 ± 1.25 1.25 ± 1.25 Crustacea Tanaidacea Zeuxo exsargasso - - - - Crustacea Tanaidacea Unidentified - - - 1.25 ± 1.25 Crustacea Ostracoda Halocyprida - - - 1.25 ± 1.25 Crustacea Ostracoda Myodocopida - 26.25 ± 13.6 - 7.5 ± 4.79 Crustacea Ostracoda Podocopida 1.25 ± 1.25 18.75 ± 5.54 1.25 ± 1.25 - Crustacea Amphipoda Caprella acanthifera - - 21.25 ± 6.25 1.25 ± 1.25 Crustacea Amphipoda Caprella liparotensis 58.75 ± 34.3 - - - Crustacea Amphipoda Phtisica marina 23.75 ± 3.15 41.25 ± 24.86 17.5 ± 4.33 45 ± 19.04 Crustacea Amphipoda Pseudoprotella phasma 181.25 ± 107.25 108.75 ± 79.38 27.5 ± 9.46 36.25 ± 5.54 Crustacea Amphipoda Mantacaprella macaronensis 235 ± 125.62 6.25 ± 3.75 27.5 ± 7.77 2.5 ± 1.44 Crustacea Amphipoda Ericthonius punctatus 33.75 ± 15.99 97.5 ± 67.78 1.25 ± 1.25 - Crustacea Amphipoda Ischyrocerus inexpectatus 1.25 ± 1.25 352.5 ± 307.61 - - Crustacea Amphipoda Microjassa cumbrensis - 23.75 ± 16.5 - - Crustacea Amphipoda Ampithoe helleri 5 ± 3.54 - - 1.25 ± 1.25 Crustacea Amphipoda Ampithoe ramondi 23.75 ± 14.05 32.5 ± 23.14 48.75 ± 19.83 122.5 ± 42.7 Crustacea Amphipoda Ampithoe sp. 3.75 ± 3.75 - 2.5 ± 2.5 - Crustacea Amphipoda Aora gracilis - - 13.75 ± 8.0 - Crustacea Amphipoda Aora spinicornis - 231.25 ± 113.53 - 41.25 ± 34.72 Crustacea Amphipoda Aora sp. - - 5 ± 2.04 7.5 ± 7.5

2

November 2011 October 2012 Functional group Group Species C. nodosa C. prolifera C. nodosa C. prolifera Crustacea Amphipoda Autonoe longipes - 1.25 ± 1.25 - - Crustacea Amphipoda Microdeutopus anomalus - - - 62.5 ± 38.11 Crustacea Amphipoda Microdeutopus damnoniensis - 12.5 ± 10.9 - - Crustacea Amphipoda Microdeutopus stationis - 465 ± 235.27 - 63.75 ± 41.6 Crustacea Amphipoda Microdeutopus sp. 3.75 ± 3.75 6.25 ± 6.25 - 7.5 ± 3.23 Crustacea Amphipoda Cheiriphotis sp. - 6.25 ± 6.25 - - Crustacea Amphipoda Corophium sp. - 2.5 ± 2.5 - - Crustacea Amphipoda Leptocheirus mariae - - - 2.5 ± 2.5 Crustacea Amphipoda Leptocheirus pilosus - 48.75 ± 45.48 1.25 ± 1.25 1.25 ± 1.25 Crustacea Amphipoda Leptocheirus sp. - 8.75 ± 8.75 - - Crustacea Amphipoda Medicorophium minimum - 1.25 ± 1.25 - - Crustacea Amphipoda Apherusa bispinosa - - 1.25 ± 1.25 46.25 ± 6.57 Crustacea Amphipoda Apherusa chiereghinii 2.5 ± 1.44 85 ± 48.95 - 10 ± 5.77 Crustacea Amphipoda Apherusa vexatrix 8.75 ± 7.18 2.5 ± 2.5 - - Crustacea Amphipoda Apherusa sp. 1.25 ± 1.25 1.25 ± 1.25 - - Crustacea Amphipoda Lysianassina longicornis - - - 21.25 ±16.38 Crustacea Amphipoda Amphilochus neapolitanus 3.75 ± 3.75 2.5 ± 2.5 - 1.25 ± 1.25 Crustacea Amphipoda Peltocoxa mediterranea - - - 1.25 ± 1.25 Crustacea Amphipoda Dexamine spinosa 10 ± 6.12 55 ± 16.2 10 ± 4.56 355 ± 96.46 Crustacea Amphipoda Liljeborgia sp. - 6.25 ± 4.73 - 1.25 ± 1.25 Crustacea Amphipoda Elasmopus sp. - 1.25 ± 1.25 - - Crustacea Amphipoda Maera inaequipes - 1.25 ± 1.25 - - Crustacea Amphipoda Harpinia sp. - 7.5 ± 4.33 - 2.5 ± 2.5 Crustacea Amphipoda Stenothoe monoculoides 11.25 ± 7.18 - 3.75 ± 2.39 - Crustacea Amphipoda Pereionotus testudo 1.25 ± 1.25 - - - Crustacea Amphipoda Microprotopus longimanus - 35 ± 23.63 - - Crustacea Amphipoda Unidentified - 3.75 ± 3.75 3.75 ± 2.39 16.25 ± 7.47 Mollusca Bivalvia Cardiidae sp. 1 - 6.25 ± 3.75 - - Mollusca Bivalvia Unidentified1 - 10 ± 5.4 3.75 ± 3.75 10 ± 2.04 Mollusca Bivalvia Unidentified2 - 3.75 ± 1.25 1.25 ± 1.25 12.5 ± 4.33 Mollusca Bittium sp. 3.75 ± 3.75 1.25 ± 1.25 - 190 ± 84.29

3

November 2011 October 2012 Functional group Group Species C. nodosa C. prolifera C. nodosa C. prolifera Mollusca Gastropoda Eulimidae sp. 1 - - - 2.5 ± 1.44 Mollusca Gastropoda Cerithiopsis sp. - - 1.25 ± 1.25 6.25 ± 4.73 Mollusca Gastropoda Nystiellidae sp. 1 8.75 ± 5.91 1.25 ± 1.25 - - Mollusca Gastropoda Alvania sp. 43.75 ± 25.2 - 6.25 ± 4.73 257.5 ± 91.3 Mollusca Gastropoda Rissoinae sp. 1 - - 16.25 ± 7.18 177.5 ± 44.37 Mollusca Gastropoda Anachis sp. - 1.25 ± 1.25 - - Mollusca Gastropoda Mitrella sp. 2.5 ± 1.44 33.75 ± 11.61 - 1.25 ± 1.25 Mollusca Gastropoda Vexillum zebrinum 11.25 ± 8.26 5 ± 3.54 - - Mollusca Gastropoda Volvarina sp. - - 1.25 ± 1.25 1.25 ± 1.25 Mollusca Gastropoda Pyramidella dolabrata - - 1.25 ± 1.25 - Mollusca Gastropoda Retusidae sp. 1 10 ± 6.12 11.25 ± 6.57 1.25 ± 1.25 77.5 ± 39.82 Mollusca Gastropoda Nudibranchia - 1.25 ± 1.25 - - Mollusca Gastropoda viridis - 8.75 ± 2.39 10 ± 2.04 1.25 ± 1.25 Mollusca Gastropoda Tricolia sp. - - 13.75 ± 4.73 7.5 ± 4.79 Mollusca Gastropoda Trochidae sp. 1 - 1.25 ± 1.25 - - Mollusca Gastropoda Turbinidae sp. 1 2.5 ± 1.44 - 1.25 ± 1.25 1.25 ± 1.25 Total abundance 768.75 ± 397.01 1975 ± 338.83 513.75 ± 196.1 2561.25 ± 769.91 Total number of species 36 65 37 58

4